docstr: Passing unsupported covariate should raise an exception
docstr_tok: ["Passing","unsupported","covariate","should","raise","an","exception"]
code: def test_backtest_bad_covariates(self, model_cls):
      """Passing unsupported covariate should raise an exception"""
      series = lt(
          start_value=1, end_value=10, length=31, dtype="float32"
      )
      model = model_cls()
      bt_kwargs = {
          "start": -1,
          "start_format": "position",
          "show_warnings": False,
      }
      model.backtest(series=series, **bt_kwargs)
  
      with pytest.raises(ValueError) as msg:
          model.backtest(
              series=series, past_covariates=series, **bt_kwargs
          )
      assert str(msg.value).startswith(
          "Model cannot be fit/trained with `past_covariates`."
      )
      if not model.supports_future_covariates:
          with pytest.raises(ValueError) as msg:
              model.backtest(
                  series=series, future_covariates=series, **bt_kwargs
              )
          assert str(msg.value).startswith(
              "Model cannot be fit/trained with `future_covariates`."
          )
  
imports: import random
  from itertools import product
  import numpy
  import pandas
  import pytest
  from darts import TimeSeries
  from darts.datasets import AirPassengersDataset, MonthlyMilkDataset
  from darts.logging import get_logger
  from darts.metrics import mape, r2_score
  from darts.models import ARIMA, FFT, ExponentialSmoothing, NaiveDrift, NaiveSeasonal, Theta
  from darts.tests.conftest import tfm_kwargs
  from darts.utils.timeseries_generation import gaussian_timeseries
  from darts.utils.timeseries_generation import linear_timeseries
  from darts.utils.timeseries_generation import random_walk_timeseries
  from darts.utils.timeseries_generation import sine_timeseries
label_desc: Use image node_id 4 for calling the TestBacktesting obj's underlying member method code with example usage: obj.test_backtest_bad_covariates(model_cls) without return types